Re: Help port swsusp to ppc.

[Nigel Cunningham]

Hi.

On Wed, 2004-01-21 at 10:54, Benjamin Herrenschmidt wrote:
> > FYI, this is that "ugly C-generated assembly" we are talking about. I
> > do not think it is so bad.
> 
> The x86 version has been cleaned up and isn't _that_ bad, though it
> could definitely use some comments and I don't like the "Lxxx" labels,
> I'd rather either use number with the "nb" or "nf" GAS constructs or
> use real words labels. Looking at it though, I fail to see the need
> to get it generated by gcc in the first place :)

The 2.4 version works from C, even the SMP version I've prepared.
Something in 2.6 is different, and I don't understand what/why (Pavel
might be able to explain). If I understood that, I could get SMP support
for 2.6 going too.

> The PPC version that was proposed is horrible.

I think he wanted help with cleaning it up.

> > FYI, there are exactly 6 variables in "nosave" section. Two loop
> > variables you can see in above code, one spinlock, number of pages to
> > save, pointer to directory of pages to be copied, and its length.
> > 
> > I could probably move spinlock and length of pgdir out of there...
> 
> That's not too much, you could probably afford having a one page header
> to the suspend image with those informations and the page copy loop
> (provided by the suspended kernel so you don't have _any_ compatibility
> issue and can even do it from the bootloader one day...)

Well, we do have a header at the moment with that info, (but not
containing the page copy loop :>)
 
> Looking at swsusp code in current 2.6, when do you do that pass ? On the
> shutdown pass, you call devices_suspend(4); which is fine. But I don't see
> where you call devices_suspend(X) on the resume path. IMHO, that should be

Hmm. Perhaps it's just my version that does it? I couldn't find it
either.

Regards,

Nigel

-- 
My work on Software Suspend is graciously brought to you by
LinuxFund.org.

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